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ALBUQUERQUE, N.M. -- West Nile virus cases in the Southwest are up from previous years, according to new 2012 statistics released by the Centers for Disease Control.

First discovered in New York around 1999, the West Nile virus traveled west, carried by birds and mosquitoes, eventually hitting the Southwest.

"2003 was the first time we actually had human cases, and we had 209 human cases that year with four of those cases being fatal," said Dr. Paul Ettestad of the New Mexico Department of Health.

Since then the number of infections here have fluctuated, with 25 cases in New Mexico in 2010; four in 2011; and 47 in 2012; making the virus hard to predict. But Ettestad says one forecast he can make is that in the Southwest, the virus will turn up near waterways.

"So along the Rio Grande, in the northwest along the San Juan and the Animas and in the southeast along the Pecos," Ettestad said. "In those areas where we have the irrigation is where we potentially have more human cases."

In Arizona, New Mexico and Nevada a total of nine West Nile virus deaths were reported last year, while California saw 20 and Texas had 89.